In timing recovery over packet networks dedicated timing packets are time-stamped by the transmitter's clock and then are sent over a packet network (PSN) to one or multiple receivers. At the receiver side, these timing packets, as they arrive, are time-stamped by the receiver clock. The difference between these two time stamps represents the relative delay between transmitter and receiver clocks, which can be used to synchronize the two clocks. FIG. 1 is an illustration of this for the case where there is one transmitter and one receiver. One of the main challenges in this synchronization approach is that the timing packets are subjected to packet delay variations (PDV) inherent in any packet networks. As a result, at the receiver side, depending on packet delay variations, the recovered reference clock will have high level of jitter and wander, which will not be acceptable for many applications, especially legacy services that assume a high quality level of synchronization.
To overcome this issue, it has been proposed to filter timing packets at the receiver such that only those timing packets that are least subjected to packet delay variations are used for clock recovery. Known methods generally rely only on a single stream of timing packets to synchronize the receiver with the transmitter.